CA1060295A - Spark-ignition internal combustion engine capable of reducing noxious constituents in exhaust gases - Google Patents
Spark-ignition internal combustion engine capable of reducing noxious constituents in exhaust gasesInfo
- Publication number
- CA1060295A CA1060295A CA249,186A CA249186A CA1060295A CA 1060295 A CA1060295 A CA 1060295A CA 249186 A CA249186 A CA 249186A CA 1060295 A CA1060295 A CA 1060295A
- Authority
- CA
- Canada
- Prior art keywords
- air
- spark
- combustion chamber
- flow amount
- internal combustion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/0015—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for using exhaust gas sensors
- F02D35/0046—Controlling fuel supply
- F02D35/0053—Controlling fuel supply by means of a carburettor
- F02D35/0061—Controlling the emulsifying air only
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D21/00—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas
- F02D21/06—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air
- F02D21/08—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M3/00—Idling devices for carburettors
- F02M3/08—Other details of idling devices
- F02M3/09—Valves responsive to engine conditions, e.g. manifold vacuum
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M7/00—Carburettors with means for influencing, e.g. enriching or keeping constant, fuel/air ratio of charge under varying conditions
- F02M7/23—Fuel aerating devices
- F02M7/24—Controlling flow of aerating air
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Control Of The Air-Fuel Ratio Of Carburetors (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
A spark-ignition internal combustion engine having a combustion chamber which is defined between a cylinder head and a piston movably disposed in a cylinder, comprising air-fuel mixture supply means for supplying air-fuel mixture into the combustion chamber; exhaust gas recirculating means for recirculating a portion of exhaust gases through an intake passage into the combustion chamber;
a plurality of spark plugs disposed within the combustion chamber for igniting the air-fuel mixture mixed with the recirculated exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be supplied from said air-fuel mixture supply means at a predetermined value in accordance with the composition of the exhaust gases.
A spark-ignition internal combustion engine having a combustion chamber which is defined between a cylinder head and a piston movably disposed in a cylinder, comprising air-fuel mixture supply means for supplying air-fuel mixture into the combustion chamber; exhaust gas recirculating means for recirculating a portion of exhaust gases through an intake passage into the combustion chamber;
a plurality of spark plugs disposed within the combustion chamber for igniting the air-fuel mixture mixed with the recirculated exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be supplied from said air-fuel mixture supply means at a predetermined value in accordance with the composition of the exhaust gases.
Description
This invention relates to ~park-ignition internal umt)ustion engines capable of effectively reducing the emission levels of noxious constituents of exhau~t ga~e.q such as nitrogen oxides, carbon monoxide and llydrocarbons.
As is well known, gasoline or petrol powered spark-ignition internal combustion engines discharge the exhaust gases containing noxious constituents such as nitrogen oxides, carbon monoxide and hydrocarbons.
Of these noxious con~tituents, carbon monoxide and hydrocarbons are the lowest in the emi.~sion level when the engine iY operated on an air-fuel mixture having ahout stoichiometric air-fuel ratio. On the contrary, the emisxion level of nitrogen oxide~ i~ the highest when operated on the about stoichiometric air-fuel mixture. Accordingly, difficultie~ have been encoun-t.ered in which the emission level of nitrogen oxides is increased as the emission levels of carbon monoxide and hydrocarbons are decrea~ed by operating the engine 011 an air-fuel mixture having a desired air-fuel ratio.
It i~, therefore, a principal object of the present invention to provide an improved spark-ignition internal combustion engine capable of effectively reducing the emission levels of noxious constituents ~5 including nitrogen oxides, carbon monoxide and :' .
~ ' q~ . .
_ ~ -10~;0295 hydrocarbons.
According to the present invention, there is provi-~e~ a sl)ark~ nitioll internal combustion engine having a combus-tion chamber which is defined between a cylinder head and a pis-ton movably disposed in a cylinder, comprising: air-fuel mixture supply means for supplying air-fuel mixture into the combustion chamber; exhaust gas recirculating means for recirculating a por-tion of exhaust gases through an intake passaye into the combus-tion chamber; a plurality of sparlt plugs disposed within the com-bustion chamber for igniting the air-fuel mixture mixed with the recirculated exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be sup-plied from said air-fuel mixture supply means at a predetermined value in accordance with the composition of the exhaust gases.
Other objects and features of the improved spark-igni-tion internal combustion engine in accordance with the present invention will become more apparent from the following descrip-tion of a preferred embodiment with reference to the accompanying drawing in which:
Fig. 1 is a schematical illustration of a spark-igni-tiOII internal combustion engine in accordance with the present invention;
106~295 Fig. Z i~ a ~chematic plan view showing a combu~-tion chamber of the engine of Fig. 1; and Fig. 3 is a cros~-sectional view of the cylinder head of the engine of Fig. 1.
~ef`erring now to the drawing, there i 9 ~hown a preferred embodiment of a spark-ignition internal combustion engine in accordnnce with the present invention, in which the engine i9 generally de~ignated by the reference numeral 10. The engine 10 has a cylinder or cylinders 12, as usual, formed in the cylinder block 14 thereof. A piston or piston~ 16 are, as customary, reciprocally dispo~ed within the cylinders 12. A combu~tion chamber or combustion chambers 18 are defined by the crown~ of the pi~tons 16 and the cylinder head 20 which is secured to the upper portion of the cylinder block 14. As viewed in Fig. 2, two spark plugs 22 are diYposed through the cylinder head 20 and projected into each of the combu~tion chambers 18 in such a manner as to be opposite to each other with respect to the center axi~ Xc of the cylinder 12 with a relatively large space therebetween. The number of the spark plugs 22 di~posed in a combugtion chamber 18 ; may be more than two.
Rach of the combustion chamber~ 18 i~ communicable throllgh an intake-port 24 and an intake valve 24a with an intake passage 26 which ls connected to the air-f`uel mixture induction pAssage 28 of a carburetor 30 or air-f`uel mixture ~upply meAns in an intake ~y~tem 32. The carburetor 30 is a8 usual communicated with an air I`ilter 34. The combustion chamber 18 i8 communicable through an exhaust port 36 and an exhaust valve 36a with an exhau~t passAge 38 of an exhauYt Yystem 40.
The exhaust pAssage 38 i~, as cu~tomary, connected to a catalytlc converter 42 or ar. exhaust ga~ purifying device for purifying exhaust gases discharged from the combustion chambers 18. As seen in ~ig. 2, the two exhaust ports of neighboring each two cylinders 12a and 12b are joined and ~iamesed in the cylinder head 20 to form a siamesed port 36. Additionally, the cylinder head 20 is formed into a cross-flow induction-exhaust arrangement in which the intake ports 24 are formed on one side of the cylinder head 20 to be communicated with the intake passage 26, whereas the exhaust ports 36 are formed on the oppo~ite ~ide of the cylinder head 20 to be communicated with the exhAust passage 38.
A conduit 44 forming part of exhaust gas recircu-lating mean~ 46 connects between the exhau~t pas~age 38 to the intake pAssAge 26 for recirculating a portion f the exhAust ga~es with thc air-fusl mixture pa~ing ' '- ' ' . ' ' .
106()295 through the intake passage 26 into the combustion chambers 18. Dispo~ed intermediate of the conduit /~4 is an exhau~t gas recirculation control valve 48 which i.s arranged to control the flow amount of the exhaust gases into the intake pas~age 26, for example, in accordance with the venturi vacuum produced in the venturi portion of the carburetor 30, the venturi vacuum being a function of the amount of the inducted air or intake air supplied into the combu~tion chambers 18 through the intake passage 26. The control valve 48 is preferably constructed snd set to control the rate of the amount of the exhauYt gases recirculated into the combustion chambers 18 in the range of from 10 to 50% to the amount of the inducted air.
It is to be noted that a high spark energy generated by the two spark plugs 22 can reliably ignite and burn even the compressed air-fuel mixture containing such a high rate of exhaust gaYe~ in the combustion chamber 18. Additionally, the burning of the compressed air-fuel mixture i~ carried out ~o that two flame flonts are produced adjacent the inner wall surface of the combustion chamber 18, a .~o-called quench area, and thereafter these flame flonts move toward the center of the combustion chamber heating it to a high tempera-ture. Accordingly, the distance of flame propagation is shortened as compared with a conventional engineu~ing only one ~park plug in a combustion chamber.
I`hlls, combustion of the air-fuel mixture i9 faster propagated and completed at the central portion of the combu~tion chamber lo, at a high temperature, thereby achieving stable and Ymooth combustion of the air-fuel mixture. This results in stable operation of the engine even when considerable amounts of exhau~t gases are presented in the combustion chamber 18.
The carburetor 30 ha~ a throttle valve 50 rotatably disposed within the air-fuel mixture induction passage 28 thereof. A main venturi portion 52 is located upstream of the throttle valve 50, and a secolldary venturi portion 54 i4 located adjacent the main venturi portion 52. Opened to the secondary venturi portion 54 is a main di~charge nozzle 56 of a main circuit which nozzle is communicated with a main well 58 which is in turn communicated with a float bowl 60 through a main fuel passage 62 having therein a main jet 63. The main well 58 has a main air bleed 64 and a first auxiliary air bleed 66. The main well 58 i9 further communicated through a restrictor 68 with a fuel passage 70 of a low-speed circuit which passage is communicated with a slow port 72 opened to the air-fuel mixture indllction passage 28 downstream of the main venturi portion 52. The fuel passage 70 has a low-4peed circuit air bleed 74 and a second auxiliary air bleed 76.
A first ~olenoid valve 78 or first air flow amount control means is disposed for opening or closing the first auxiliary air bleed 66 and arranged to take a first state wherein the actuating rod 78a thereof i9 ~:
moved with respect to the first auxiliary air bleed 66 to increase the flow amount of air inducted through the first auxiliary air bleed 66 into the main well 58 than a predetermined level, wherea3 take a second state wherein the actuating rod or member 78a thereof is moved with respect to the first auxiliary air bleed 66 to decrease the flow amount of the air inducted through the auxiliary air bleed 66 into the main well 58 than the predetermined level. A second solenoid valve 80 or second air flow control mean~ is electri-cally connected in parallel with the first solenoid valve 78 and arranged to be operated similarly to the first solenoid valve 78. The first and second solenoid valves 78 and 80 form part of air_fuel ratio control means 82 and electrically connected to a control circuit 84.
The control circuit 84 is arranged to generate a first command signal for placing the first and second olenoid valves 78 and 80 into the first state and a second command ~ignal for placing the first and second solenoid valve~ 78 and 80 into the second state. The control circuit 84 is electrically connected to an exhaust gas sensor 86 which is di~po~ed within the - exhAust passage 38 of the exhaust system 40 upstream of the catalytic converter 42. The exhaust gas sen~or ~ -86 is arranged to generate e first information ~ignal (which may be a voltage signal) for causing the control circuit 84 to generate the first command signal when the exhaust gases passing through the exhaust passage 38 have a first composition representing that the com- ;-bustion chamber3 18 are fed with an air-fuel mixture richer than a predetermined level such as stoichio-- 15 metric air-fuel ratio (14.8 : 1), and a second infor-mation signal for cauYing the control circuit 84 to - generate the second command signal when the exhau~t gaseq passing through the exhaust passage 38 have a second composition representing that the combustion chambers 18 are fed with an air-fuel mixture leaner than the predetermined level. The exhaust gas sensor 86 may be an oxygen (2) sensor, a nitrogen oxides (NOx) sensor, a carbon monoxide (C0) sensor, a carbon dioxides (C02) sensor or a hydrocarbon (HC) sensor which are respectively detect the concentration of 2 ...
., ~
.
~.
106C~Z95 .~Ox, C0, C02 or ~IC contained in the exhau~t ga~e~
discharged from the combu~tion chamber~ 18. The catalytic converter 42 may be an oxidation catalytic converter, a reduction catalytic converter, or a three-way catalytic converter capable of reducing NOx as well a~ oxidizing C0 and HC, or may be replaced with a thermal reactor. In order to operate the fir4t and second air flow amount control means 78 and 80 itl t}le above di~cuY~ed manner, the control circuit 84 may be tO arranged to set, as a reference voltage, a specified voltage signal generated by the exhaust gas sen~or o6 when the predetermined level of the air-fuel mixture is ~upplied into the combustion chambers, and to generate the first command signal when the level of the voltage signal from the sen~or 86 iq lower than that of the ~pecified voltage ~ignal representing that the combustion chambers are fed with the air-fuel mixture leaner than the predetermined level and the qecond command signal when the level of the voltage ~ignal from the ~en~or 86 is higher than that of the specified voltage signal representing that the combustion chambers are fed with the air-fuel mixture richer than the predetermined level.
Wi-th the arrangement hereinbefore di~cus~ed, during the operation of the engine 10, a relatively _ ~ _ :
. ~
:- : ' 106~)Z9~ ~
large amount of the exhaust gases is introduced from the exhau~t pa~sage 38 through the conduit 44 of the exhau~t ga~ recirculating means 46 into the intake pa~sage 26 and thereafter inducted, with the air-fuel mixture prepared by the carburetor 30, into the com-bustion chambers 18. The air-fuel mixture containing the exhaust gases i~ ignited and effectively burned by the two spark plugs 22 disposed within each the combustion chamber 18. Due to the effect of the recirculated exhauYt gases, the maximum temperature within the combustion chambers 18 is lowered and accordingly the emission level of NOx is reduced as compared with the engine without the exhaust gas recirculating means.
When the combu~tion chambers 18 are fed with the air-fuel mixture richer than the predetermined level such as stoichiometric air-fuel ratio, the first and second solenoid valves 78 and 80 are operated to increase the flow amounts of air inducted respectively through the first and second auxiliary air bleed~ 66 and 76 into the main well 58 and the fuel passage 70 of the low-speed circuit. Then, the flow amounts of fuel through the main nozzle 56 asld the slow port 72 are decrea~ed and accordingly the air-fuel mixture fed into the combu~tion chamber~ 18 are made leaner.
(~ ::
_ ,~ _ ~06~)29S
On the contrary, when the combustion chambers 18 are fed with the air-fllel mixture leaner than the pre-determined level, the first and second solenoid valve~
78 and 80 are operated to decrea~e the flow amount of air inducted respectively through the first and second auxiliary air bleeds 66 and 76 into the main well 58 and the fuel passage 70 of the low-~peed circuit.
Then, the flow amount~ of fuel through the main nozzle 56 and the slow port 72 are increased and accordingly, the air-fuel mixture fed into the combustion chambers 18 are enriched. As di~cussed above, the air-fuel mixture Yupplied into the combustion chambers 18 can be always maintained accurately at the predetermined level such as the stoichiometric air-fuel ratio.
While only the Yolenoid valves 78 and 80 of the type wherein the air flow amount~ into the main well 58 and the fuel passage 70 are controlled in on and off manner are shown and described, it will be under-stood that meanY for controlling the air flow amount in a continuous manner may be u~ed in place of the solenoid valves 78 and 80.
The present invention provideR a variety of advantages which may be stated as follows:
1. Since relatively large amounts of the exhaust gases are recirculated in the combustion chamber~, .. . .
~ - \
ttle emission level of NOx is greatly lowered and tendency liable to occur knocking of the engine is decrea~ed.
Accordingly, increase of the compression ratio of the engine and raising the upper limit of the engine coolant temperature can be possible causing increase of engine output power and improvement in fuel consump-tion. -
As is well known, gasoline or petrol powered spark-ignition internal combustion engines discharge the exhaust gases containing noxious constituents such as nitrogen oxides, carbon monoxide and hydrocarbons.
Of these noxious con~tituents, carbon monoxide and hydrocarbons are the lowest in the emi.~sion level when the engine iY operated on an air-fuel mixture having ahout stoichiometric air-fuel ratio. On the contrary, the emisxion level of nitrogen oxide~ i~ the highest when operated on the about stoichiometric air-fuel mixture. Accordingly, difficultie~ have been encoun-t.ered in which the emission level of nitrogen oxides is increased as the emission levels of carbon monoxide and hydrocarbons are decrea~ed by operating the engine 011 an air-fuel mixture having a desired air-fuel ratio.
It i~, therefore, a principal object of the present invention to provide an improved spark-ignition internal combustion engine capable of effectively reducing the emission levels of noxious constituents ~5 including nitrogen oxides, carbon monoxide and :' .
~ ' q~ . .
_ ~ -10~;0295 hydrocarbons.
According to the present invention, there is provi-~e~ a sl)ark~ nitioll internal combustion engine having a combus-tion chamber which is defined between a cylinder head and a pis-ton movably disposed in a cylinder, comprising: air-fuel mixture supply means for supplying air-fuel mixture into the combustion chamber; exhaust gas recirculating means for recirculating a por-tion of exhaust gases through an intake passaye into the combus-tion chamber; a plurality of sparlt plugs disposed within the com-bustion chamber for igniting the air-fuel mixture mixed with the recirculated exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be sup-plied from said air-fuel mixture supply means at a predetermined value in accordance with the composition of the exhaust gases.
Other objects and features of the improved spark-igni-tion internal combustion engine in accordance with the present invention will become more apparent from the following descrip-tion of a preferred embodiment with reference to the accompanying drawing in which:
Fig. 1 is a schematical illustration of a spark-igni-tiOII internal combustion engine in accordance with the present invention;
106~295 Fig. Z i~ a ~chematic plan view showing a combu~-tion chamber of the engine of Fig. 1; and Fig. 3 is a cros~-sectional view of the cylinder head of the engine of Fig. 1.
~ef`erring now to the drawing, there i 9 ~hown a preferred embodiment of a spark-ignition internal combustion engine in accordnnce with the present invention, in which the engine i9 generally de~ignated by the reference numeral 10. The engine 10 has a cylinder or cylinders 12, as usual, formed in the cylinder block 14 thereof. A piston or piston~ 16 are, as customary, reciprocally dispo~ed within the cylinders 12. A combu~tion chamber or combustion chambers 18 are defined by the crown~ of the pi~tons 16 and the cylinder head 20 which is secured to the upper portion of the cylinder block 14. As viewed in Fig. 2, two spark plugs 22 are diYposed through the cylinder head 20 and projected into each of the combu~tion chambers 18 in such a manner as to be opposite to each other with respect to the center axi~ Xc of the cylinder 12 with a relatively large space therebetween. The number of the spark plugs 22 di~posed in a combugtion chamber 18 ; may be more than two.
Rach of the combustion chamber~ 18 i~ communicable throllgh an intake-port 24 and an intake valve 24a with an intake passage 26 which ls connected to the air-f`uel mixture induction pAssage 28 of a carburetor 30 or air-f`uel mixture ~upply meAns in an intake ~y~tem 32. The carburetor 30 is a8 usual communicated with an air I`ilter 34. The combustion chamber 18 i8 communicable through an exhaust port 36 and an exhaust valve 36a with an exhau~t passAge 38 of an exhauYt Yystem 40.
The exhaust pAssage 38 i~, as cu~tomary, connected to a catalytlc converter 42 or ar. exhaust ga~ purifying device for purifying exhaust gases discharged from the combustion chambers 18. As seen in ~ig. 2, the two exhaust ports of neighboring each two cylinders 12a and 12b are joined and ~iamesed in the cylinder head 20 to form a siamesed port 36. Additionally, the cylinder head 20 is formed into a cross-flow induction-exhaust arrangement in which the intake ports 24 are formed on one side of the cylinder head 20 to be communicated with the intake passage 26, whereas the exhaust ports 36 are formed on the oppo~ite ~ide of the cylinder head 20 to be communicated with the exhAust passage 38.
A conduit 44 forming part of exhaust gas recircu-lating mean~ 46 connects between the exhau~t pas~age 38 to the intake pAssAge 26 for recirculating a portion f the exhAust ga~es with thc air-fusl mixture pa~ing ' '- ' ' . ' ' .
106()295 through the intake passage 26 into the combustion chambers 18. Dispo~ed intermediate of the conduit /~4 is an exhau~t gas recirculation control valve 48 which i.s arranged to control the flow amount of the exhaust gases into the intake pas~age 26, for example, in accordance with the venturi vacuum produced in the venturi portion of the carburetor 30, the venturi vacuum being a function of the amount of the inducted air or intake air supplied into the combu~tion chambers 18 through the intake passage 26. The control valve 48 is preferably constructed snd set to control the rate of the amount of the exhauYt gases recirculated into the combustion chambers 18 in the range of from 10 to 50% to the amount of the inducted air.
It is to be noted that a high spark energy generated by the two spark plugs 22 can reliably ignite and burn even the compressed air-fuel mixture containing such a high rate of exhaust gaYe~ in the combustion chamber 18. Additionally, the burning of the compressed air-fuel mixture i~ carried out ~o that two flame flonts are produced adjacent the inner wall surface of the combustion chamber 18, a .~o-called quench area, and thereafter these flame flonts move toward the center of the combustion chamber heating it to a high tempera-ture. Accordingly, the distance of flame propagation is shortened as compared with a conventional engineu~ing only one ~park plug in a combustion chamber.
I`hlls, combustion of the air-fuel mixture i9 faster propagated and completed at the central portion of the combu~tion chamber lo, at a high temperature, thereby achieving stable and Ymooth combustion of the air-fuel mixture. This results in stable operation of the engine even when considerable amounts of exhau~t gases are presented in the combustion chamber 18.
The carburetor 30 ha~ a throttle valve 50 rotatably disposed within the air-fuel mixture induction passage 28 thereof. A main venturi portion 52 is located upstream of the throttle valve 50, and a secolldary venturi portion 54 i4 located adjacent the main venturi portion 52. Opened to the secondary venturi portion 54 is a main di~charge nozzle 56 of a main circuit which nozzle is communicated with a main well 58 which is in turn communicated with a float bowl 60 through a main fuel passage 62 having therein a main jet 63. The main well 58 has a main air bleed 64 and a first auxiliary air bleed 66. The main well 58 i9 further communicated through a restrictor 68 with a fuel passage 70 of a low-speed circuit which passage is communicated with a slow port 72 opened to the air-fuel mixture indllction passage 28 downstream of the main venturi portion 52. The fuel passage 70 has a low-4peed circuit air bleed 74 and a second auxiliary air bleed 76.
A first ~olenoid valve 78 or first air flow amount control means is disposed for opening or closing the first auxiliary air bleed 66 and arranged to take a first state wherein the actuating rod 78a thereof i9 ~:
moved with respect to the first auxiliary air bleed 66 to increase the flow amount of air inducted through the first auxiliary air bleed 66 into the main well 58 than a predetermined level, wherea3 take a second state wherein the actuating rod or member 78a thereof is moved with respect to the first auxiliary air bleed 66 to decrease the flow amount of the air inducted through the auxiliary air bleed 66 into the main well 58 than the predetermined level. A second solenoid valve 80 or second air flow control mean~ is electri-cally connected in parallel with the first solenoid valve 78 and arranged to be operated similarly to the first solenoid valve 78. The first and second solenoid valves 78 and 80 form part of air_fuel ratio control means 82 and electrically connected to a control circuit 84.
The control circuit 84 is arranged to generate a first command signal for placing the first and second olenoid valves 78 and 80 into the first state and a second command ~ignal for placing the first and second solenoid valve~ 78 and 80 into the second state. The control circuit 84 is electrically connected to an exhaust gas sensor 86 which is di~po~ed within the - exhAust passage 38 of the exhaust system 40 upstream of the catalytic converter 42. The exhaust gas sen~or ~ -86 is arranged to generate e first information ~ignal (which may be a voltage signal) for causing the control circuit 84 to generate the first command signal when the exhaust gases passing through the exhaust passage 38 have a first composition representing that the com- ;-bustion chamber3 18 are fed with an air-fuel mixture richer than a predetermined level such as stoichio-- 15 metric air-fuel ratio (14.8 : 1), and a second infor-mation signal for cauYing the control circuit 84 to - generate the second command signal when the exhau~t gaseq passing through the exhaust passage 38 have a second composition representing that the combustion chambers 18 are fed with an air-fuel mixture leaner than the predetermined level. The exhaust gas sensor 86 may be an oxygen (2) sensor, a nitrogen oxides (NOx) sensor, a carbon monoxide (C0) sensor, a carbon dioxides (C02) sensor or a hydrocarbon (HC) sensor which are respectively detect the concentration of 2 ...
., ~
.
~.
106C~Z95 .~Ox, C0, C02 or ~IC contained in the exhau~t ga~e~
discharged from the combu~tion chamber~ 18. The catalytic converter 42 may be an oxidation catalytic converter, a reduction catalytic converter, or a three-way catalytic converter capable of reducing NOx as well a~ oxidizing C0 and HC, or may be replaced with a thermal reactor. In order to operate the fir4t and second air flow amount control means 78 and 80 itl t}le above di~cuY~ed manner, the control circuit 84 may be tO arranged to set, as a reference voltage, a specified voltage signal generated by the exhaust gas sen~or o6 when the predetermined level of the air-fuel mixture is ~upplied into the combustion chambers, and to generate the first command signal when the level of the voltage signal from the sen~or 86 iq lower than that of the ~pecified voltage ~ignal representing that the combustion chambers are fed with the air-fuel mixture leaner than the predetermined level and the qecond command signal when the level of the voltage ~ignal from the ~en~or 86 is higher than that of the specified voltage signal representing that the combustion chambers are fed with the air-fuel mixture richer than the predetermined level.
Wi-th the arrangement hereinbefore di~cus~ed, during the operation of the engine 10, a relatively _ ~ _ :
. ~
:- : ' 106~)Z9~ ~
large amount of the exhaust gases is introduced from the exhau~t pa~sage 38 through the conduit 44 of the exhau~t ga~ recirculating means 46 into the intake pa~sage 26 and thereafter inducted, with the air-fuel mixture prepared by the carburetor 30, into the com-bustion chambers 18. The air-fuel mixture containing the exhaust gases i~ ignited and effectively burned by the two spark plugs 22 disposed within each the combustion chamber 18. Due to the effect of the recirculated exhauYt gases, the maximum temperature within the combustion chambers 18 is lowered and accordingly the emission level of NOx is reduced as compared with the engine without the exhaust gas recirculating means.
When the combu~tion chambers 18 are fed with the air-fuel mixture richer than the predetermined level such as stoichiometric air-fuel ratio, the first and second solenoid valves 78 and 80 are operated to increase the flow amounts of air inducted respectively through the first and second auxiliary air bleed~ 66 and 76 into the main well 58 and the fuel passage 70 of the low-speed circuit. Then, the flow amounts of fuel through the main nozzle 56 asld the slow port 72 are decrea~ed and accordingly the air-fuel mixture fed into the combu~tion chamber~ 18 are made leaner.
(~ ::
_ ,~ _ ~06~)29S
On the contrary, when the combustion chambers 18 are fed with the air-fllel mixture leaner than the pre-determined level, the first and second solenoid valve~
78 and 80 are operated to decrea~e the flow amount of air inducted respectively through the first and second auxiliary air bleeds 66 and 76 into the main well 58 and the fuel passage 70 of the low-~peed circuit.
Then, the flow amount~ of fuel through the main nozzle 56 and the slow port 72 are increased and accordingly, the air-fuel mixture fed into the combustion chambers 18 are enriched. As di~cussed above, the air-fuel mixture Yupplied into the combustion chambers 18 can be always maintained accurately at the predetermined level such as the stoichiometric air-fuel ratio.
While only the Yolenoid valves 78 and 80 of the type wherein the air flow amount~ into the main well 58 and the fuel passage 70 are controlled in on and off manner are shown and described, it will be under-stood that meanY for controlling the air flow amount in a continuous manner may be u~ed in place of the solenoid valves 78 and 80.
The present invention provideR a variety of advantages which may be stated as follows:
1. Since relatively large amounts of the exhaust gases are recirculated in the combustion chamber~, .. . .
~ - \
ttle emission level of NOx is greatly lowered and tendency liable to occur knocking of the engine is decrea~ed.
Accordingly, increase of the compression ratio of the engine and raising the upper limit of the engine coolant temperature can be possible causing increase of engine output power and improvement in fuel consump-tion. -
2. The emission level of HC is lowered consider-ably since complete combu~tion within the combustion chambers is promoted due to the fact that the combus-tion is initiated adjacent to the inner wall surface of each combustion chamber or the so-called quench area. -~
3. The air-fuel ratio of the air-fuel mixture supplied into the combustion chambers is always aCCII-rately maintained at stoichiometric one end therefore ;
variations in the emi~sion levels of NOx, C0 and HC
are minimized providing more accurate and improved control of noxious constituents in the exhaust gases.
variations in the emi~sion levels of NOx, C0 and HC
are minimized providing more accurate and improved control of noxious constituents in the exhaust gases.
4. The improvement in engine output power and exhaust gas control is accomplished by increasing thevolumetric efficiency and the ~cavenging efficiency of the engine ~ince the engine employs a cross-flow induction-exhaust cylinder head.
5. If the engine is equipped with an afterburner such as a thermal reactor for reburning the unburned _ ~V
', ' ', .:
constituent~ in the exhaust gase4 discharged from the combustion chambers, the afterburner is maintained at a high temperature sufficient to accomplish therewithin oxidation reaction of the unburned constituents in the exhau~t gases since the engine employs siamesed ports wherein two exhaust ports of neighboring two combustion chamber~ are siamesed within the cylinder head of the engine.
It will now be appreciated from the foregoing description that, according to the present invention, the emission level of NOx iY lowered by recirculating a relatively large amount of the exhaust gases into the combustion chambers, and the emission level~ of C0 and HC are lowered by supplying the combustion chambers with the airrfuel mixture having ~toichio-metric air-fuel ratio at which the minimum emission levels of C0 and HC is obtained. In addition, the exhaust gases discharged from the combustion chambers supplied with the stoichiometric air-fuel mixture allows to effectively accomplish the purification of the noxious constituents of the exhaust gases within the exhaust gas purifying device particularly the three-way catalytic converter.
.
- -: - ' , , , , ~
, . . . ..
', ' ', .:
constituent~ in the exhaust gase4 discharged from the combustion chambers, the afterburner is maintained at a high temperature sufficient to accomplish therewithin oxidation reaction of the unburned constituents in the exhau~t gases since the engine employs siamesed ports wherein two exhaust ports of neighboring two combustion chamber~ are siamesed within the cylinder head of the engine.
It will now be appreciated from the foregoing description that, according to the present invention, the emission level of NOx iY lowered by recirculating a relatively large amount of the exhaust gases into the combustion chambers, and the emission level~ of C0 and HC are lowered by supplying the combustion chambers with the airrfuel mixture having ~toichio-metric air-fuel ratio at which the minimum emission levels of C0 and HC is obtained. In addition, the exhaust gases discharged from the combustion chambers supplied with the stoichiometric air-fuel mixture allows to effectively accomplish the purification of the noxious constituents of the exhaust gases within the exhaust gas purifying device particularly the three-way catalytic converter.
.
- -: - ' , , , , ~
, . . . ..
Claims (19)
1. A spark-ignition internal combustion engine having a combustion chamber which is defined between a cylinder head and a piston movably disposed in a cylinder, comprising:
air-fuel mixture supply means for supplying air-fuel mixture into the combustion chamber;
exhaust gas recirculating means for recirculating a portion of exhaust gases through an intake passage into the combustion chamber;
a plurality of spark plugs disposed within the combustion chamber for igniting the air-fuel mixture mixed with the recirculated exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be supplied from said air-fuel mixture supply means at a predetermined value in accordance with the composition of the exhaust gases.
air-fuel mixture supply means for supplying air-fuel mixture into the combustion chamber;
exhaust gas recirculating means for recirculating a portion of exhaust gases through an intake passage into the combustion chamber;
a plurality of spark plugs disposed within the combustion chamber for igniting the air-fuel mixture mixed with the recirculated exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be supplied from said air-fuel mixture supply means at a predetermined value in accordance with the composition of the exhaust gases.
2. A spark-ignition internal combustion engine as claimed in Claim 1, in which said air-fuel mixture supply means includes a carburetor having a main discharge nozzle opened into the venturi portion of the carburetor, a main well communicated through a main fuel passage with the main discharge nozzle and communicated with the float bowl of the carburetor, a main air bleed communicated with the main well for introducing therethrough the atmospheric air into the main well, and a first auxiliary air bleed communicated with the main well for introducing therethrough the atmospheric air into the main well.
3. A spark-ignition internal combustion engine as claimed in Claim 2, in which said air-fuel ratio control means includes:
first air flow amount control means for controlling flow amount of air inducted through the first auxiliary air bleed into the main well, said first air flow amount control means being operated electrically and arranged to take a first state wherein the flow amount of the air is increased than a pre-determined level and a second state wherein the flow amount of the air is decreased than the predetermined level;
control circuit electrically connected to said air flow amount control means and arranged to generate a first command signal to place said air flow amount control means into the first state and a second command signal to place said air flow amount control means into the second state;
an exhaust gas sensor disposed within the exhaust gas passage of the exhaust system communicated with downstream of the combustion chamber of the engine and electrically connected to said control circuit, said exhaust gas sensor being arranged to generate a first information signal for causing said control circuit to generate the first command signal when the exhaust gases passing through the exhaust passage have a first composition representing that the combustion chamber is fed with an air-fuel mixture richer than a predetermined level, and a second information signal for causing said control circuit to generate the second command signal when the exhaust gases passing through the exhaust passage have a second composition represent-ing that the combustion chamber is fed with an air-fuel mixture leaner than the predetermined level.
first air flow amount control means for controlling flow amount of air inducted through the first auxiliary air bleed into the main well, said first air flow amount control means being operated electrically and arranged to take a first state wherein the flow amount of the air is increased than a pre-determined level and a second state wherein the flow amount of the air is decreased than the predetermined level;
control circuit electrically connected to said air flow amount control means and arranged to generate a first command signal to place said air flow amount control means into the first state and a second command signal to place said air flow amount control means into the second state;
an exhaust gas sensor disposed within the exhaust gas passage of the exhaust system communicated with downstream of the combustion chamber of the engine and electrically connected to said control circuit, said exhaust gas sensor being arranged to generate a first information signal for causing said control circuit to generate the first command signal when the exhaust gases passing through the exhaust passage have a first composition representing that the combustion chamber is fed with an air-fuel mixture richer than a predetermined level, and a second information signal for causing said control circuit to generate the second command signal when the exhaust gases passing through the exhaust passage have a second composition represent-ing that the combustion chamber is fed with an air-fuel mixture leaner than the predetermined level.
4. A spark-ignition internal combustion engine air-claimed in Claim 3, in which said air flow amount control means includes a first solenoid valve having an actuating member which is arranged to be moved with respect to the first auxiliary air bleed to increase the flow amount of air inducted through the first auxiliary air bleed into the main well than the pre-determined level upon receiving the first command signal from the control circuit, and moved with respect to the first auxiliary air bleed to decrease the flow amount of the same air than the predetermined level upon receiving the second command signal from said control circuit.
5. A spark-ignition internal combustion engine as claimed in Claim 4, in which said exhaust gas recircu-lating means includes a conduit means connected between the exhaust passage communicated downstream of the combustion chamber and the intake passage communicated upstream of the combustion chamber, and control valve means for controlling the flow amount of the recircu-lated exhaust gases at a predetermined rate with respect to the flow amount of the air inducted into the com-bustion chamber.
6. A spark-ignition internal combustion engine as claimed in Claim 5, in which said predetermined rate is in the range of from 10 to 50% by volume of the air inducted into the combustion chamber.
7. A spark-ignition internal combustion engine as claimed in Claim 6, in which said plurality of the spark plugs are two spark plugs.
8. A spark-ignition internal combustion engine as claimed in Claim 7, in which said two spark plugs are disposed through the cylinder head of the engine to project into the combustion chamber, said two spark plugs being located opposite to each other with respect to the center axis of the cylinder.
9. A spark-ignition internal combustion engine as claimed in Claim 3, in which said carburetor further includes a fuel passage for the low-speed circuit of the carburetor, said fuel passage communicating the main fuel passage through a restrictor with a flow port opened to the air-fuel mixture induction passage downstream of the venturi portion of the carburetor, a low-speed circuit air bleed communicated with the fuel passage, and a second auxiliary air bleed communicated with the fuel passage for introducing therethrough the atmospheric air into the fuel passage.
10. A spark-ignition internal combustion engine as claimed in Claim 9, in which said air-fuel ratio control means further includes second air flow amount control means for controlling the flow amount of air inducted through the second auxiliary air bleed into the fuel passage of the low-speed circuit, said second air flow amount control means being operated electrically and electrically connected in parallel with the first air flow amount control means, and arranged to take a first state wherein the flow amount of air is increased than a predetermined level and a second state wherein the flow amount of the same air is decreased than the pre-determined level, said second air flow control means being placed into the first state upon receiving first command signal from said control circuit and into the second state upon receiving the second command signal from said control circuit.
11. A spark-ignition internal combustion engine as claimed in Claim 10, in which said second flow amount control means icnludes a second solenoid valve having an actuating member which is arranged to be moved with respect to the second auxiliary air bleed to increase the flow amount of air inducted through the second auxiliary air bleed into the fuel passage of the low-speed circuit than the predetermined level upon receiving the first command signal from said control circuit, and moved with respect to the second auxiliary air bleed to decrease the flow amount of the same air than the predetermined level upon receiving the second command signal from said control circuit.
12. A spark-ignition internal combustion engine as claimed in Claim 1, further comprising an exhaust gas purifying device communicable with the combustion chamber for oxidizing unburned constituents in the exhaust gases discharged from the combustion chamber.
13. A spark-ignition internal combustion engine as claimed in Claim 12, said exhaust gas purifying device includes an oxidation catalytic converter communicable with the combustion chamber for oxidizing carbon monoxide and hydrocarbons in the exhaust gases discharged from the combustion chamber.
14. A spark-ignition internal combustion engine as claimed in Claim 12, said exhaust gas purifying device includes reduction catalytic converter communicable with the combustion chamber for reducing nitrogen oxides in the exhaust gases discharged from the combus-tion chamber.
15. A spark-ignition internal combustion engine as claimed in Claim 12, said exhaust gas purifying device includes a three-way catalytic converter arranged to reduce nitrogen oxides and oxidize carbon monoxide and hydrocarbons in the exhause gases.
16. A spark-ignition internal combustion engine as claimed in Claim 3, in which said exhaust gas sensor is an oxygen sensor for detecting the concentration of oxygen contained in the exhaust gases discharged from the combustion chambers.
17. A spark-ignition internal combustion engine as claimed in Claim 1, in which said cylinder head is formed into a cross-flow induction-exhaust arrangement.
18. A spark-ignition internal combustion engine as claimed in Claim 1, in which the engine has at least two combus-tion chambers, the exhaust ports of the two combustion chambers being siamesed within the cylinder head to form a siamesed exhaust port.
19. A spark-ignition internal combustion engine having a combustion chamber defined by a cylinder head and a piston crown, comprising:
air-fuel mixture supply means for supplying an air-fuel mixture into the combustion chamber, said air-fuel mixture supply means including an intake passage communicable with the combustion chamber and a throttle valve disposed in the intake passage;
exhaust gas recirculating means for recirculating a portion of exhaust gases with the air-fuel mixture into the com-bustion chamber, said exhaust gas recirculating means including conduit means which connects an exhaust passage of the engine with the intake passage downstream of the throttle valve;
a plurality of spark plugs disposed within the com-bustion chamber for reliably igniting the air-fuel mixture mixed with the recirculated exhaust gases;
a three-way catalytic converter communicable through the exhaust passage with the combustion chamber to purify the noxious constituents in the exhaust gases discharged from the com-bustion chamber, said three-way catalytic converter being designed to reduce nitrogen oxides and oxidize carbon monoxide and hydro-carbons in the exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be supplied from said air-fuel mixture supply means at stoichiometric value in accordance with the composition of the exhaust gases, in order to accomplish ef-fective purification of noxious constituents in said three-way catalytic converter, whereby the emission levels of nitrogen oxides, car-bon monoxide and hydrocarbons in the exhaust gases are considera-bly decreased improving fuel consumption.
air-fuel mixture supply means for supplying an air-fuel mixture into the combustion chamber, said air-fuel mixture supply means including an intake passage communicable with the combustion chamber and a throttle valve disposed in the intake passage;
exhaust gas recirculating means for recirculating a portion of exhaust gases with the air-fuel mixture into the com-bustion chamber, said exhaust gas recirculating means including conduit means which connects an exhaust passage of the engine with the intake passage downstream of the throttle valve;
a plurality of spark plugs disposed within the com-bustion chamber for reliably igniting the air-fuel mixture mixed with the recirculated exhaust gases;
a three-way catalytic converter communicable through the exhaust passage with the combustion chamber to purify the noxious constituents in the exhaust gases discharged from the com-bustion chamber, said three-way catalytic converter being designed to reduce nitrogen oxides and oxidize carbon monoxide and hydro-carbons in the exhaust gases; and air-fuel ratio control means for controlling air-fuel ratio of the air-fuel mixture to be supplied from said air-fuel mixture supply means at stoichiometric value in accordance with the composition of the exhaust gases, in order to accomplish ef-fective purification of noxious constituents in said three-way catalytic converter, whereby the emission levels of nitrogen oxides, car-bon monoxide and hydrocarbons in the exhaust gases are considera-bly decreased improving fuel consumption.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP50040143A JPS51114528A (en) | 1975-04-01 | 1975-04-01 | Fuel control device in internal combustion engines |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1060295A true CA1060295A (en) | 1979-08-14 |
Family
ID=12572544
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA249,186A Expired CA1060295A (en) | 1975-04-01 | 1976-03-30 | Spark-ignition internal combustion engine capable of reducing noxious constituents in exhaust gases |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS51114528A (en) |
| CA (1) | CA1060295A (en) |
| DE (1) | DE2613586C2 (en) |
| GB (1) | GB1531552A (en) |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2191746A (en) * | 1938-03-02 | 1940-02-27 | Jean A H Barkeij | Combustion chamber in cylinder heads of internal combustion engines |
| US3696618A (en) * | 1971-04-19 | 1972-10-10 | Universal Oil Prod Co | Control system for an engine system |
| JPS5118023B2 (en) * | 1972-04-14 | 1976-06-07 | ||
| DE2219880A1 (en) * | 1972-04-22 | 1973-10-25 | Bosch Gmbh Robert | DEVICE FOR REGULATING THE COMPOSITION OF A FUEL-AIR MIXTURE FOR A COMBUSTION ENGINE |
| JPS4967024A (en) * | 1972-11-01 | 1974-06-28 | ||
| FR2237065B1 (en) * | 1973-07-03 | 1978-12-01 | Peugeot & Renault | |
| JPS5153131A (en) * | 1974-11-01 | 1976-05-11 | Nissan Motor | Kikaki |
| JPS5154132A (en) * | 1974-11-08 | 1976-05-13 | Nissan Motor | Nainenkikanno nenryoseigyosochi |
-
1975
- 1975-04-01 JP JP50040143A patent/JPS51114528A/en active Pending
-
1976
- 1976-03-30 CA CA249,186A patent/CA1060295A/en not_active Expired
- 1976-03-30 GB GB12695/76A patent/GB1531552A/en not_active Expired
- 1976-03-30 DE DE2613586A patent/DE2613586C2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51114528A (en) | 1976-10-08 |
| GB1531552A (en) | 1978-11-08 |
| DE2613586C2 (en) | 1986-01-09 |
| DE2613586A1 (en) | 1976-10-14 |
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